1. Field of the Invention
The present invention relates to a recording medium in which a spare area which is used as an alternative to a defective sector is properly arrange, and relates to a storing apparatus. More particularly, the invention relates to a recording medium in which a recording surface is divided into a plurality of zones and an alternate area is provided every zone and relates to a storing apparatus.
2. Description of the Related Arts
Hitherto, as rewritable recording media for optically recording and reproducing information, a magneto-optical recording medium and a phase change recording medium are known. In the magneto-optical recording medium, a magnetic material is used for a recording film, a heating by light and a change in magnetization by a magnetic field are used for recording, and a magneto-optical effect is used for reproduction. In the phase change recording medium, the degree of temperature according to a difference in power by the heating by light is used for recording and a change in reflectance according to a crystal state of the recording film is used for reproduction. In such optical recording media, a spare area to be used as an alternative when a recording area becomes unusable due to a defect on the medium or the like is provided. When the recording area is divided into a plurality of groups, the spare area which is used for alternative use (alternation) is provided at the end of each group. For example, although a magneto-optical disk cartridge of 90 mm and 128 MB according to ISO/IEC 10090 uses the CAV system, the recording area can be divided into groups of arbitrary integers of 1 to 1024 upon formatting. The spare area for alternation is provided at the end of each group and the number of spare sectors per group is the same. The capacity of the spare area which can be arranged on the medium is limited by an interface with an upper apparatus. In case of an SCSI interface, for instance, the number of spare sectors which can be arranged in the medium is limited to 2248 sectors (about 4.6 MB). Consequently, the maximum number of spare sectors which can be arranged in each group is obtained by:
(the number of sectors per group)=(2248 sectors)/(the number of groups)
Since a magneto-optical disk cartridge of 90 mm and 230 MB according to ISO/IEC 13963 uses the ZCAV system, the recording area is divided into 10 zones. All of the zones can be used either as one group or 10 groups by using each zone as one group. When the zones are used as 10 groups, the spare area is provided for every zone and the number of spare sectors per zone is equal to, for example, 204 and is the same. Further, a magneto-optical disk cartridge of 90 mm and 640 MB according to ISO/IEC 15041 also uses the ZCAV system. Therefore, in case of 512 bytes/sector, there are 18 zones. In case of 2048 bytes/sector, there are 11 zones. The spare area for alternation is provided for each zone. In this case as well, the number of spare sectors per zone is the same. For instance, it is equal to 124 sectors in case of 18 zones and is equal to 204 sectors in case of 11 zones.
In the optical recording media as mentioned above, when the recording area is divided into the zones, the spare area for alternation which is allocated to each zone has sectors of the number obtained by dividing a predetermined total number of spare sectors within the maximum number of spare sectors which can be allocated to the medium by the number of zones irrespective of the recording capacity of each zone. On the contrary, since the probability of alternation due to a defect or the like on the medium is uniform at any position, the number of sectors to be alternated in one zone is larger as the position approaches the outer circumference side where the number of sectors in the zone is larger. Consequently, if the spare areas have been fully used for alternation in the same zone, the spare area in another zone is used as an alternation destination. When a defective sector which has been alternated to the spare area of another zone is accessed, however, the reciprocation to/from the other zone is needed for an alternating process and a time which is required to seek becomes long by such an amount. There is a problem that the accessing performance deteriorates.
In the case where the capacity of the optical recording medium is relatively small to be 128 MB or 230 MB, even if a predetermined number of spare sectors are allocated to each zone, a difference between the capacity of the innermost zone and that of the outermost zone is not so large. Even in the zone on the outer side where the capacity is large, a situation such that the self spare area is fully used does not occur. When the capacity of the optical recording medium is increased to, for example, 640 MB, however, if the spare sectors of the same number are arranged, a possibility such that the self spare area is fully used in the zone on the outer side where the capacity is large rises. When the capacity of the optical recording medium is further increased to, for example, 1.3 GB which is twice as large as the capacity of the medium of 640 MB, the possibility such that the self spare area is fully used in the zone on the outer side where the capacity is large further rises. There is a problem that the accessing performance deteriorates by using the spare area, as an alternation destination, in the other zone.
According to the invention, there is provided a recording medium in which when a spare area which is alternately used is provided every zone, a spare area in the same zone is used as an alternation destination without using a spare area in another zone, thereby enabling the accessing performance to be maintained.
According to the invention, there is provided a recording medium in which data is recorded on a recording surface. The recording medium has a plurality of zones obtained by dividing the recording surface into a plurality of regions in the radial direction and a plurality of spare areas which are provided every zone and are used for alternation of a defective sector, wherein the number of spare logical tracks or the number of spare logical sectors occupied by the spare area in each zone is determined on the basis of a spare ratio K obtained from a total capacity of the spare areas for a total capacity of data areas on the recording surface and a capacity of the data area of each zone. Consequently, the spare area in each zone has a proper capacity according to the data area, an inconvenience such that the spare areas are fully used by the alternation due to a defect on the medium or the like and the spare area in another zone is alternated can be solved even on the outer side where the data capacity is large, and an alternating process effectively utilizing the limited spare areas can be executed even when the data capacity increases. The number of spare logical tracks or the number of spare logical sectors occupied by the spare area in each zone is set to an integer value determined on the basis of a value obtained by multiplying the number of logical tracks or the number of sectors of the data area in each zone by the spare ratio K. The spare ratio not only is set to be constant in each zone but also can be weighted so that the spare ratio increases as the track position approaches the outer circumference. This method is an optimum allocation of the spare areas in which a fact that a margin decreases as the track position approaches the outer circumference is considered. By setting the number of spare logical tracks or the number of spare logical sectors occupied by the spare area in each zone to an integer value as mentioned above, an address conversion at the time of the process for alternating the defective sector becomes easy, and a burden which is required by the alternating process on the storing apparatus side is lightened, so that the process can be executed at a high speed. When the number of user data zones on the recording surface is equal to 18 and the total number of spare logical tracks in the user data zone is equal to 132, the numbers of spare logical tracks of the zones directing from the outer side of user zone toward the inner side are sequentially equal to 9, 9, 9, 9, 8, 8, 8, 8, 7, 7, 7, 7, 7, 6, 6, 6, 6, and 5. When the number of user data zones on the recording surface is equal to 11 and the total number of spare logical tracks in the user data zone is equal to 132, the numbers of spare logical tracks of the zones directing from the outer side of the user zone toward the inner side are sequentially equal to 15, 14, 14, 13, 13, 12, 11, 11, 10, 10, and 9. The recording medium has a recording and reproducing structure of a magnetically induced super resolution (MSR) in which at least a recording layer for recording data at a recording density smaller than a beam diameter of a laser beam and a reproducing layer for reproducing the data recorded in the recording layer by a combination of a reproducing magnetic field and a reproducing laser power are formed on a substrate.
According to another embodiment of the invention, there is provided a recording medium comprising a plurality of zones obtained by dividing a recording surface into a plurality of regions at a pitch interval in the radial direction and a plurality of spare areas which are provided every zone and are used for alternation of a defective sector, wherein the pitch interval of the spare areas of each zone is determined on the basis of a spare ratio K which is obtained from a total capacity of the spare areas for a total capacity of data areas on the recording surface and the pitch interval of each zone. In this case as well, the spare ratio not only is made constant in each zone but also can be weighted so that the spare ratio increases as the track position approaches the outer circumference. The recording medium has a recording and reproducing structure of the magnetically induced super resolution (MSR) in which at least a recording layer for recording data at a recording density smaller than a beam diameter of a laser beam and a reproducing layer for reproducing the data recorded in the recording layer by a combination of a reproducing magnetic field and a reproducing laser power are formed on a substrate.
According to the invention, there is provided a storing apparatus in which when a spare area which is used for alternation is provided every zone in a recording medium, a spare area in the same zone is used as an alternation destination without using the spare area in another zone, thereby enabling the accessing performance to be maintained.
A storing apparatus of the invention comprises a recording unit, a reproducing unit, and a defect processing unit. The recording unit has a plurality of zones obtained by dividing the recording surface into a plurality of regions in the radial direction and a plurality of spare areas which are provided every zone and are used for alternation of a defective sector. The recording unit records data to a recording medium in which a ratio of (the number of spare logical tracks occupied by the spare area in each zone)/(the number of sectors) is determined on the basis of a spare ratio K obtained from a total capacity of the spare areas for a total capacity of data areas on the recording surface and a capacity of the data area of each zone. The reproducing unit reproduces the data on the recording medium. When a defective sector on the recording medium is detected, the defect processing unit allows an alternating process for allocating an alternate sector to a spare area in a zone to which the defective sector belongs and allowing the alternate sector to be used to be executed. That is, when a defective sector due to the format of the recording medium is detected, the defect processing unit allows a subsequent normal sector to be used and executes a slipping process for slipping a sector overflowed from the data area into the spare area in the zone. When a defective sector is detected after the formatting, the defect processing unit executes an alternating process for allocating an alternate sector to the spare area in the zone and allowing the alternate sector to be used. In the recording medium for recording data by the recording unit, the number of spare logical tracks or the number of spare logical sectors occupied by the spare area in each zone is set to an integer value determined on the basis of a value obtained by multiplying the number of logical tracks or the number of sectors of the data area in each zone by the spare ratio K. When the number of user data zones on the recording surface of the recording medium to which data is recorded by the recording unit is equal to 18 and the total number of spare logical tracks in the user data zone is equal to 132, the numbers of spare logical tracks of the zones directing from the outer side of the user zone toward the inner side are sequentially equal to 9, 9, 9, 8, 8, 8, 8, 7, 7, 7, 7, 7, 6, 6, 6, 6, 5, and 5. When the number of the user data zones of the recording surface of the recording medium on which data is recorded by the recording unit is equal to 11 and the total number of spare logical tracks in the user data zone is equal to 132, the numbers of spare logical tracks of the zones directing from the outer side of the user zone toward the inner side are sequentially equal to 15, 14, 14, 13, 13, 12, 11, 11, 10, 10, and 9. The recording medium has a recording and reproducing structure of super resolution (MSR) in which at least a recording layer for recording data at a recording density smaller than a beam diameter of a laser beam and a reproducing layer for reproducing the data recorded on the recording layer by a combination of a reproducing magnetic field and a reproducing laser power are formed on a substrate of the recording medium for recording data by the recording unit. Further, the recording unit or the reproducing unit executes a recording or reproducing control according to the zone CAV system.
According to another embodiment of the storing apparatus of the invention, a recording unit comprises a plurality of zones obtained by dividing a recording surface into a plurality of regions at a pitch interval in the radial direction of the recording surface and a plurality of spare areas which-are provided every zone and are used for alternation of a defective sector. Data is recorded to a recording medium in which the pitch interval of the spare areas of each zone is determined on the basis of a spare ratio K obtained from a total capacity of the spare areas for a total capacity of data areas on the recording surface and the pitch interval of the zones. A reproducing unit reproduces the data recorded on the recording medium. When a defective sector in the recording medium is detected, a defect processing unit allows an alternating process such that an alternate sector is allocated to a spare area in a zone to which the defective sector belongs and the alternate sector is used to be executed. In this case as well, when a defective sector due to the format of the recording medium is detected, the defect processing unit allows the subsequent normal sectors to be used and executes a slipping process for slipping the final sector into the spare area in the zone. When a defective sector is detected after the formatting, an alternating process for allocating an alternate sector to the spare area in the zone and allowing the alternate sector to be used is performed. A recording medium for recording data by the recording unit has a recording and reproducing structure of super resolution (MSR) in which at least a recording layer for recording data at a recording density smaller than a beam diameter of a laser beam and a reproducing layer for reproducing the data recorded on the recording layer by a combination of a reproducing magnetic field and a reproducing laser power are formed on a substrate. Further, a recording unit or a reproducing unit of the storing apparatus executes a recording or reproducing control by the zone CAV system.
The above and other objects, features, and advantages of the present invention will become more apparent from the following detailed description with reference to the drawings.